EXTENSIVE REPROGRAMMING OF PRIMARY AND SECONDARY METABOLISM BY FUNGALELICITOR OR INFECTION IN PARSLEY CELLS

The transcription rates of numerous plant genes have previously been s hown to be strongly affected by pathogen infection or elicitor treatme nt, Here we estimate the extent and complexity of this response by ana lyzing the patterns of mRNA induction in fungal elicitor-treated parsl ey cells (Petroselinom crispum) for several representatives from vario us primary and secondary metabolic pathways, cytosolic as well as plas tidic, As a reference, we use the biphasic accumulation curve for the coordinately induced mRNAs encoding the three core enzymes of general phenylpropanoid metabolism, phenylalanine ammonia-lyase, cinnamate 4-h ydroxylase and 4-coumarate:CoA ligase, Coincidence with this curve was observed for the mRNA induction kinetics of several, but not all, phe nylpropanoid branch pathway-related reactions, whereas seven selected mRNAs from the pentose phosphate, glycolytic and shikimate pathways, i ncluding various cytosolic anti plastidic isoforms, were induced with great differences in timing. Likewise unique and dissimilar from the r eference curve were the induction patterns for various mRNAs encoding enzymes or proteins that are either more distantly or not at all relat ed to phenylpropanoid metabolism, None of over 40 mRNAs tested so far remained unaffected, Using one strongly elicitor-responsive mRNA from carbohydrate metabolism, encoding a cytosolic glucose 6-phosphate dehy drogenase, for in situ RNA/RNA hybridization in fungus-infected parsle y leaf tissue, we observed again the previously reported, close simula tion of metabolic changes in true plant/fungus interactions by elicito r treatment of cultured cells, In addition to demonstrating extensive, highly complex functional, temporal and spatial patterns of changes i n gene expression in infected plant cells, these results provide valua ble information for the identification of pathogen-responsive promoter s suitable for gene technology-assisted resistance breeding.